The present invention is directed to a mobile hoist system and method, components therefor, and/or units, assemblies, or subsystems thereof. More particularly, the present invention concerns an improved hoist, lift, or elevator system, components, assemblies, units, or subsystems thereof especially adapted for use in connection with billboards, signs, marquees, sign boards, displays, and the like.
In the construction industry or building industry, it is well known to use on-site erectable or portable elevators, hoists, cages, lifts, or the like for moving personnel and building materials up the side of a building under construction. Such known elevators, hoists, cages, lifts, or the like have suffered from the drawbacks of being extremely complex, difficult to set up on-site, difficult to maintain, difficult to disassemble or take down, unsafe, difficult to operate, and the like.
Holland (U.S Pat. No. 3,313,376) discloses a lightweight elevator which in one configuration includes an L-shaped track member, a gear rack attached to the track member and adapted to receive a pinion gear at the free end of the output shaft of a motor attached to a platform. The motor is controlled from the ground by a suitable switch means through a current lead.
Pearson (U.S. Pat. No. 5,065,845) discloses a speed governor safety device for stopping an elevator car.
Johansson (U.S. Pat. No. 3,866,717) discloses a rack and pinion elevator with at least two racks, a plurality of drive motors, and a speed safety brake.
U.S. Pat. Nos. 151,014; 1,080,846; 1,032,320; 1,264,847; 210,693; and 76,693 disclose elevator safety devices.
Pichon (U.S. Pat. No. 4,557,353) discloses a service elevator for construction.
O'Connell (U.S. Pat. No. 1,931,237) discloses an elevator guide including a dovetail or wedge-shaped track.
Maurer (U.S. Pat. No. 394,781) discloses a convertible scaffold and fire escape including uprights having a T-shaped head on the front face thereof and having a racked front face adapted to engage a pinion gear.
D'Alessio et al. (U.S. Pat. No. 4,516,663) discloses a safety device for a rack and pinion hoist including a frangible rack section of reduced dimensions adapted to disintegrate and thereby disengage the rack in case of malfunction.
Shohet (U.S. Pat. No. 3,924,710) and Iida (U.S. Pat. No. 3,804,208) disclose rack and pinion hoist apparatus.
White (U.S. Pat. No. 2,757,755) discloses a portable elevator.
Bono (U.S. Pat. No. 4,706,779) discloses a transportable twin-telescopic arm platform hoist including a twin-arm telescopic unit, a carriage with a work platform mounted on the twin-arm unit, and a self-propelled or towed vehicle supporting the twin-arm unit on a pivoting platform.
Hiergeist (U.S. Pat. No. 3,866,718) discloses a reeling device for load and safety ropes or cables on suspended outdoor elevator-type cages and having a single reeling drum on which the load and safety ropes or cables are wound.
Pratt (U.S. Pat. No. 5,312,218) discloses a folding apparatus for positioning objects into structures.
Montaigne et al. (U.S. Pat. No. 4,865,155) discloses a high-rise fire fighting and rescue system including an external elevator system which piggybacks a first rail car on top of a second rail car to permit transfer of the first rail car to an upper setback section of a high-rise building. Each rail car is equipped with pinion drives that engage racks fixed to vertical rails attached to faces of the building. The cars also have motor driven wheels that allow the car to drive on horizontal surfaces.
Hence, there exists a need for an improved mobile hoist system and method incorporating at least a transportable or movable cage, lift, or platform, and which is relatively simple in construction, safe, and easy to use.